Question #9f4fd

1 Answer
May 3, 2016

As a blended material:

#26 34/41 %# of the 1:10 material
#73 7/41 % # of the diluting material
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Or: add 30 more measures of the diluting material

Explanation:

#color(blue)("Preamble about ratios")#

Consider the ratio of 1:10.

This consists of 1 part of something added to 10 parts of something else. So the total amount of parts is 11.

Thus a 1:10 ratio is a concentration of #1/11xx100 = 9.09bar09%#

Where the bar means repeating for ever.

And 1:40 #-> 1/41xx100 ~~2.439%" "#to 3 decimal places
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#color(blue)("Solving your question")#

You have a #1:10# that you need to change to #1:40#

#color(blue)("Condition 1")#

#color(brown)("It does not matter that you have more volume/weight")#

What ever you use to measure the 10 use to measure a further 30 giving you #1:(10+30)->1:40#

#color(blue)("Condition 2")#
#color(brown)("You wish to blend the two so that have a specific volume/weight")#

#color(brown)("Some people do not like the following method but it works very well.")#

I use the principle of a straight line graph to plot the change in concentration as you gradually add more and more of one of the constituent. Thus able to determine the exact blend needed.

Tony B

The bottom axis measures the amount of diluting constituent from none at all to nothing but the diluting constituent.

#color(brown)("What follows is saying: the gradient of the little bit is the same all of it!")#
So we have:#" "x-:30/451=100-:1/11" "#

#" "x xx451/30=100xx11/1#

#" "x=(100xx11xx30)/(451)#

#x=73 7/41 % # diluting material (exact value)

The amount of the original; 1:10 mixture is:

#100-73 7/41 = 26 34/41 %# exact value
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Check

# 26 34/41 xx1/100xx 1/11 =1/41" "color(red)("This works so ok!")#